1 2The SGI Visual Workstations (models 320 and 540) are based around
3the Cobalt, Lithium, and Arsenic ASICs. The Cobalt ASIC is the
4main system ASIC which interfaces the 1-4 IA32 cpus, the memory
5system, and the I/O system in the Lithium ASIC. The Cobalt ASIC
6also contains the 3D gfx rendering engine which renders to main
7system memory -- part of which is used as the frame buffer which
8is DMA'ed to a video connector using the Arsenic ASIC. A PIIX4
9chip and NS87307 are used to provide legacy device support (IDE,
10serial, floppy, and parallel).
11 12The Visual Workstation chipset largely conforms to the PC architecture
13with some notable exceptions such as interrupt handling.
14